Process of dephosphorizing iron ores



' 'ilED STATES PATENT OFFrcE.

WilZLIAM F. PHILLIPS, OF BIRMINGHAM, ALABAMA.

PROCESS OF DEPHOSPHORIZING lRQN ORES.

EiPECIFIGATION forming part of Letters Patent NO. 5423 71, dated July 2, 1895-.

Application filed November 18,1393. Serial 150.491.1332. (No specimens.)

To (l/ZZ whom if may concern..-

Be it known that 1, WILLIAM B. PHILLIPS, a citizen oi the United States, residing at Birmingham, Jefferson county, Alabama, have invented certain nowand useful Improvements in irocesses oiDephosphorizing iron Ores, of which the following is a specification.

My invention relates to the treatmentof iron ores .tor the purpose of reducing the phosphorus contained in such ores to and below the Bessemer limit, or entirely elimihating such deleter ous element, whereby the treated ore maybe rendered suitable for making steel.

.lieretoiere it has been thought impossible to economically remove phosphorus from iron me. by chemical treatment, so as to reduce this ingredient to and below the Bessemer limit; and it has been proposed to treat ores which. have already suites-ed a substantial loss of phosphorus by mechanical magnetic treatment. The ores thus treated have been those ores which contain phosphorousbearing compounrlaeuch as crystalsot' apatite, and it hecn possible to partially remove the phosphorus from such ores by mechanical n agnetic treatment, and then by chemical tr at to dissolve out the remaining percent; phosphorous-bearing compound by chcini action. cannot be or". any effect as applied to those ores found largely in the Southern States of this country, known the red fossilores;

is to this variety of ores that my preis particularly applicable, for reasons which will appear hereinafter, as my process is disclosed in the description to follow.

carrying out my new process 1. have proceeded upon the discovery which Ihave made that dilute sulphuric acid, either heated or cold vill dissolve out the phosphorus Within the or without materially affecting the per centcge of iron-in otherwords,itwill reduce the amount of phosphorus contained in cross, such as the red hematitcs or red fossil ores, mentioned above,without reducing materially the percentage of iron in the ore, thereby producing a. Bessemer ore suitable foi the purposes of making steel.

To enable those skilled in the art to understand how my process is or can be caried out, i will describe one way in which it have Such a process, however,

applied it, which I have found to be very effectual.

I first take the ore as it is mined andcrush it, so that it may pass, preferably, through a four-inch ring. Then the ore is'magnetized Thoroughly by bringing it to a bright red heat by any suitable means, and while thus heated pass over and 'through it a current of reducing-gas. The action of this gas upon the heated ore is to render the ore thoroughly magnetic. The magnetized ore is now pulverized and treated on a magnetic separator of any well-known or approved construction, by which treatment the silica, sand, due, but not the phosphorus, are in great part eliminated. Without limiting myself to the use of. any particular degree of fineness, I may state that a screen from about eight to ten mesh gives good results. In this treatment by the separator the phosphorus accompanies the heads, While the other ingredients mentioned pass into the tails, and these magnetic heads now contain the iron mixed with the phosphorus. The heads are then to be treated with dilute sulphuric acid. This is effected in any suitable way by pouring the acid upon the magnetized ore, which is placed in vessels or suitable receptacles, so that the acid may thoroughly mix with and act upon every particle of the ore. 01? course it will be understood that the mixture of acid and ore is to be agitated by any suitable means for the purpose of elfectiug a thorough mixture. After the acid has acted upon the ore a sufficient length of time, depending on the percentage of phosphorus in the ore, it is run or pourcdotf and may he used over again on fresh ore, or recovered as such. If one treatment with acid be found not; sufficient for the purpose, the ore may be treated further with fresh acid until thedesired result is effected. The ore should then be thoroughly Washed with Water in order to remove the last trace of acid, as well as such phosphorous compounds as have -been rendered soluble in Water or acidified Water.

it will be observed in this process that the phosphorus is not removed by the magnetic concentration, but goes with the magnetized iron ore in the magnetic beads, so that the after treatment by the acid is the means whereby the phosphorus is reduced or removed without materially affecting the percentage of iron in the ore. This is because of the fact that the,redfossil ores contain phosphorus not in crystallized compounds, which can be magnetically or mechanically removed.

By my process I am enabled expeditiously and economically to 'j'reduce the content of phosphorus in the fossil ores to and below the Bessemerlii'nit, or to remove it entirely, whereby the ore is rendered suitable for steel-male ing by the Bessemer process.

As a practical example 'of the results obtained by my process, I "may state that I have taken magnetic concentrates containing above fifty-five per cent. of iron, below fourteen per cent. silica, and from 0.35 per cent. to 0.40 per cent. phosphorus,and reduced'the phosphorus to such an extent that the one after treatment contains less than 0.04 per. cent, and even as little as 0.08per cent. phosphorus, by which it is seen that theprocess is effectual in dephosphorizing the ore.

I have not described any particular apparatus for carrying out the diiferent steps of my process, since it is obvious that any suitable Well-knownheating chamber or furnace may be used for heating the ore preparatory to its treatment upon the con cen t-rator, which latter may, as stated, be of any approved form, while the reducing-gas may be conveyed by suitable pipes or passages from the source of supply to thehating-chamber, and

'ized in any suitable grinding or pulverizing the ore, after magnetization, may be pulver- 35 apparatus. Lastly, the treatment by the acid may be carried on in tanks or vessels of the form and capacity desired.

The proportions of acid to the ore may be governed by circumstances within the knowledge of the skilled metallurgist; but I have found that good results may be obtained by using about twenty-five per cent., by weight, of acid to the ore, though I do not wish to be understood as limiting myself in this or any other matter of detail, as the proportion of acid to the ore, the degreeof dilution of the acid, &o., which latter may be about 12 Baum, are all details that may be varied without departing from the spiritof my invention.

I claim as my invention-- The process of dephosphorizing iron ore' which oonsistsin rendering the ore magnetic I by suhjectingvthe ore while highly heated to the act-ion. of. a rcducing gas, then magneti- 55 cally-concentrating the ore thus treated, and

finally subjecting the concentrated ore to the action of dilute sulphuric acid, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

M. B. PHILLIPS.

Witnesses:

1 HARRY Y. DAVIS,

R. T. FRAZIER. 

